As with PC Arc/INFO, which was due to be discontinued around 1994 I think, but which we still develop and support because of ongoing international demand, my opinion is that ESRI will continue with AV3.x as long as there are uses and demand for it. 

It's a good idea to try to pick up some VB where you can, but part of my job is to represent the needs and problems of users with very limited staff and budget resources and it's plain to me that even those able to undertake converting avenue code to VB will need several years to do it. My assumption is that most non-profit users will rely on the tools that work now for the tasks in front of them, and that no non-profit group has the resources for code conversion. 

Until someone does it for them pro-bono or some dedicated soul does it personally (the way most ArcScripts are done), they'll stick with 3.x. An important factor in any upgrade or purchase decision is to consider the amount of third-party add-ons especially if they are free! 

At this moment, ESRI's free Arcscipts page has 140 offerings in VB, and 1,483 offerings in Avenue. One way to decide when to migrate to VB is when there are 10 times as many VB scripts as avenue, rather than 1/10th. 

Charles Convis
ESRI Conservation Program Coordinator
ecp2@esri.com
380 New York St, Redlands, CA 92373
Tel: (909) 793-2853 x2488
website: http://www.conservationgis.org/